Hot-rolled metal strip is wound into coils immediately after the rolling operation and then has to be cooled. Once it has been wound into coils, the metal strip cools only slowly and a large area is therefore needed for storing the coils during the cooling process. With steel strip, in particular, slow cooling in the open air is also disadvantageous as a thick, hard layer of scale would form on the strip and, in addition to the disadvantage of considerable wastage of material, this would also complicate the pickling process necessary before further processing of the strip, for example by cold rolling. It is therefore usual to cool the coils of wound metal strip quickly using water, and this used to be effected by immersing the coils in water or by sprinkling or spraying the coils with water. The quantity and type of scale is favourably influenced by rapid cooling. Thus, scale is formed to a particularly significant extent in the case of steel at temperatures ranging between 750.degree. and 450.degree. C. and the quantity of scale is smaller, the shorter the time the strip remains in this temperature range. In addition, the free atmospheric oxygen is prevented from reaching the metal during immersion of the coils and this also suppresses the formation of scale.
This cooling operation with water surrounding the coils on all sides is therefore given preference. The disadvantage of this cooling operation lies in the fact that the apparatuses required are very complicated, therefore expensive and, as they have to function in part under water, also require maintenance. Another disadvantage is that the coils cannot be observed visually when they are immersed.
The object of the invention is to permit rapid cooling of the coils while simultaneously preventing the admission of free oxygen and enabling the coils to be observed visually in a simple manner.